A multi cyclone block of an air cleaner known from the market has a plurality of cyclone cells. Each cyclone cell has a cell-inlet, where the raw air streams in a hood having at a hood-inlet and a hood-outlet for the air to be cleaned. The hood is connected air-ducting with the cell-inlets by the hood-outlet. The cyclone cells separate particles from the air to be cleaned. The separated particles being collected in the cyclone block. The collected particles must be removed from the cyclone block at regular maintenance intervals. Therefore, a scavenging system is required. Such hoods are also sometimes referred to as cowls.
It is an object of the invention to provide a hood and an air cleaner of the above-mentioned kind, where a pre-separation efficiency (PSE) for particles can be improved and/or a maintenance interval can be extended and/or a maintenance can be simplified.